Inflammatory Gene Expression in Goats in Response to Transport

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Transport, a common cause of stress in livestock, has been documented to increase cortisol, and epinephrine in goats. However, little is known about the timing of changes in the immune system in these stressed animals. The objective of this study was to determine whether expression of immune-related genes changes in goats that are exposed to transport stress. In this study, 15 Spanish-Boer goats ranging from 3 to 4 yrs of age were transported for 12 h. Goats were divided into 5 groups of 3 and placed in 1.219 m x 1.219 m pens. Blood samples were collected via jugular veni-puncture from each animal at 0 h, 3 h, 6 h, 9 h, and 12 h of transport, plasma and leukocytes were harvested for cortisol analysis and PCR analysis for gene expression. Data was analyzed using trailer location (group) as the experimental unit in a mixed model, repeated measures analysis of variance with compound symmetry and autoregressive covariance structures, depending on the best fit for each model. Percent weight losses were analyzed using a diagonal covariance mixed model. Hourly temperature humidity index (THI) values inside the trailer and from the shade were analyzed using a two-independent sample T-test. Cortisol concentrations were significantly elevated during transport (P<.049), indicating that goats experienced stressful events during hours of transport. Cortisol concentrations peaked after 6 hours, and returned to near basal concentrations after 12 h of transport. There was an overall trend for greater expression of many of the genes of interest to increase expression after 12 h of transport, but none were significantly different from pre-transport expression values. Overall, the data suggests that the goats transported during this study experienced transport stress, as indicated by the elevation in cortisol concentrations, but did not have significant changes in expression of the immune-related genes after 12 h of transport.